The term "water-based functional fluid" is used herein to refer to water-based lubricants, hydraulic fluids, cutting fluids and the like. Water-based functional fluids are not a new concept. However, in recent times, the increasing cost and scarcity of petroleum has made it increasingly desirable to replace oil-based functional fluids with water-based functional fluids wherever possible. Other benefits can also flow from such replacements such as decreased fire hazard and environmental pollution problems. In many cases, however, it is not feasible to make such replacements because the water-based functional fluids cannot be modified in their properties so as to perform to the same high degree as their oil-based counterparts. For example, it has been often difficult, if not impossible to replace certain oil-based hydraulic fluids with water-based fluids even though the desirability of doing so is evident.
Various E.P. agents, load-carrying and anti-wear agents have been proposed for use in water-based functional fluids. Most of these agents have, however, been found to be ineffective in imparting desired E.P., load-carrying or anti-wear properties, or have been found to be too toxic.
Carboxylic acid derivatives made from high molecular weight carboxylic acid acylating agents and amino compounds and their use in oil-based lubricants are known. See, for example, U.S. Pat. Nos. 3,216,936; 3,219,666; 3,502,677; and 3,708,522.
Phosphorus-containing and phosphorus- and sulfur-containing acids and their use in oil-based lubricants are also known. See, for example, U.S. Pat. No. 4,289,635.
It would be advantageous to provide improved ashless E.P., load-carrying and anti-wear agents suitable for use in water-based functional fluids. It would be particularly advantageous if these agents were satisfactorily non-toxic.